There are many process streams in commercial processing facilities, including facilities in the chemical, petrochemical, polymerization, oil, and gas industries, which contain two or more fluid components. Examples of process streams containing two or more fluid components include: polymerization process streams, ethane cracker process streams, natural gas process streams, syngas process streams, biomass gasification process streams, Fischer-Tropsch process streams, alkane dehydrogenation process streams, and alcohol dehydration process streams. Sometimes it is desirable to separate the fluid components of a process stream so as to “upgrade” the process stream and/or to recover a fluid component of value.
Separation techniques include conventional distillation, absorption using ionic liquid membranes, and absorption using aqueous solutions of metal salts. Distillation requires a large number of stages and/or high reflux ratios when fluid components have close boiling points and can be cost-prohibitive. Ionic liquid membranes are limited by membrane diffusion rates and can have poor flux or require significant capital expenditure for commercial applications. The water in an aqueous solution of metal salts has a significant vapor pressure which makes recovery of the separated component from the aqueous solution inefficient (e.g., water is typically carried with the component after the component is separated from the aqueous solution, requiring de-watering).
There is an ongoing need for improved separation techniques for process streams in commercial processing facilities.